JPS59140769A - Document optical scanner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises at least two linear optical transducers, an optical system for imaging an elongated portion of a document onto said transducers, and an optical system for imaging an elongated portion of a document onto said transducers; , a movable part for moving a part in a direction perpendicular to the longitudinal direction of the part.

A device of this type is known, for example, from European Patent No. 27,878. It is preferred to use two or more photoelectric converters when relatively large documents must be scanned with crystal resolution. For example, the width of approximately 217 battles is l s
For scanning with a resolution of 11.8 lines per m (800 lines per inch), the transducer must have 2560 photoelectric elements.

Commercially available transducers have up to 2048 photoelectric elements, but even if in the future they can be used for long conversions, they will be relatively expensive. The price per optoelectronic element generally increases in practice as the number of optoelectronic elements per converter increases. Therefore, it is often necessary to use 2111 or more transducers. In the known device, the light from the document is thus split by an optical element into two beams, which pass through an objective mirror and form an image on transducers arranged diagonally one above the other. The two images together, in some cases to some extent, reproduce an elongated portion of the document with a length equal to the width of the document. This optical element has two reflective circles, but these reflective surfaces must make a precisely defined angle with respect to each other, and their direction must also be precisely defined. Therefore, strict precision is required in its manufacture. The objective must produce two accurate images of the scanned portion of the document, which also places stringent demands on the objective. Because the transducers are arranged diagonally one above the other, there is little space above or below the transducers for auxiliary electronic circuits, such as control circuits or signal preamplifiers.

The object of the invention is to obtain a device of the type mentioned at the outset, in which the optical system can be constructed from relatively simple and inexpensive components and in which there is room for auxiliary circuitry in the immediate vicinity of the transducer.

A feature of the present invention is that the image portion of the transducer has N longitudinally adjacent narrow stripes, N being an integer greater than 1, and the device has N narrow strips between adjacent transducers. The optical system has N linear photoelectric converters arranged uniformly with a space between them, and the optical system has N image threads each having a converter attached thereto. This is due to the fact that a training device was installed to move the target.

Since each imaging thread only needs to image a relatively narrow strip of the document onto its associated transducer, the imaging threads are relatively simple and inexpensive. Furthermore, by choosing a different number of transducers and associated image threads, it is possible to vary the length of the image section (and thus the width of the document) and/or the resolution. The spacing of the transducers in line allows room for auxiliary circuitry beside and between the transducers.

In a preferred embodiment of the invention, the trimming device is configured such that the strips imaged by the image thread onto the transducer can be easily selected so that these strips cover the entire width of the document. , along the optical axis of the imaging system and 2 perpendicular to this optical axis.
movement in one direction and rotation about an axis perpendicular to the optical axis and the longitudinal axis of the transducer.

The present invention will be explained in detail below with reference to embodiments of the drawings.

The device of FIG. 1 has a housing 1, the upper side of which has a transparent part 8 which serves as a table for the text vJ5 to be scanned. Directly below this table is a first carriage 7 which is moved along the first rule system 9 parallel to the table in the direction of the arrow 11 a distance at least equal to the length of the document 6. Said carriage is pulled by a cable 18 which is passed via guide rollers 15 to a cable drum 17. The cable drum 1f is driven by an electric motor 19, which is connected to the cable drum via a slip joint 21 and a transmission 23. A tachometer 25 is provided to control the electric motor 19.

The first carriage 7 has two light sources 819, for example, tubes,
These light sources illuminate the document 5. The light reflected from the illuminated portion of the document passes through a hole 88 in the bottom of the first carriage and passes through a first plane mirror 8 attached to the first carriage by a support 87.
It is reflected at 5. The plane of this plane mirror makes an angle of 45° with the light ray 89 emerging from the document 5. This ray, shown as a dashed line in the drawing, is reflected by the mirror at an angle of 90° and is directed to the first carriage 7.
parallel to the direction of motion 11.

Said light beam 89 then passes through the second plane mirror 41 and the eighth plane mirror 4.
8, mirror 6 reflects with an angular deviation of 90°, so that the light ray is reflected with a total angle of 180° and is then directed in a direction opposite to the direction of movement of the first carriage 7. The second plane mirror 41 and the eighth plane mirror 48 are attached to a second carriage 47 by a support 45, and this second carriage 47 is attached to the second carriage 47.
It is moved along the rail system 49 in a direction 51 parallel to the direction of movement 11 of the first carriage 7. The second round trip,
A pulley 52 is attached to the stand 47, a cable 58 is passed to this pulley, and one end of the cable is connected to the first carriage 7.
The other end is attached to the nousing J. As a result, the second carriage moves in the same direction as the first carriage, but at half the speed of the first carriage. The second carriage 47 is further connected to one end of a spring 59 via a cable 55 passed to a guide roller 57, and the other end of this spring is connected to the housing 1.
is connected to. When the two carriages are moved to the left by rotation of the motor 19 in one direction, the springs are released, and when the motors are rotated in the opposite direction, the springs return the carriages to their original position.

After being reflected by the eighth plane mirror 43, the light ray 89 hits a number of camera systems, which create an image of the thin strip of the document 5 on a linear photoelectric converter, which converts the image into an electrical signal. and stored in a storage device or otherwise processed. A camera system 61, one of which is shown in FIG. 1, is mounted on the housing 1 on a beam 68. During the interlocking movement of the first carriage 7, the imaged strip is moved across the length of the document 5 at right angles to its longitudinal direction, so that the document body is scanned. It goes without saying that if necessary, the first carriage 7 may be moved a shorter distance in order to scan only the required portions of the document. Since the second and eighth plane mirrors 41 and 43 each move at half the speed of the first plane mirror 85 in the same direction, the optical path length of the light ray 89 is constant for all positions of the two carriages 7 and 47. 0, so that a high sharpness image is always obtained in the area of the photoelectric converter. FIG. 2 is a detailed view of one of the camera systems 61 with a group of photoelectric converters.

The photoelectric converter 65 has a large number of photosensitive elements (for example, 512, 1024, 1728, or 2048) arranged next to each other on a straight line. The converter 65 is mounted on a printed circuit board 67 which also includes auxiliary circuitry (not shown) for controlling the converter and amplifying the output signal.

Said printed circuit board 67 is attached to the back plate 71 of the camera 78 by bolts with spacer sleeves 69. Camera 7B forms camera string 61 with transducer 65, and may be housed within protective housing 741 if desired. The back plate 71 is connected to the front &
77, this front plate is provided with a threaded sleeve 79. For this purpose, the rear surface of the back plate 71 is provided with a vertical U-shaped slot (not shown) in which the yoke of the coupling member 75 is located.

Although the connection between the U-shaped connecting member 75 and the front plate 77 is a fixed connection, the back plate 71 is vertically adjustable relative to the connecting member as indicated by arrow 81. For this purpose, an adjusting screw 88 is provided on the underside of the coupling member 75, which screw presses against the lower end of the back plate 71. A compression spring 85 is provided on the upper side of the connecting member 75, and this spring presses the upper edge of the back plate 71. When the adjustment screw 88 is turned upward by the screwdriver 87, the back plate 71 moves upward, while when the m-section screw is turned downward, the barb 85 pushes the back plate downward. The back plate '/1 can be pressed against the coupling member 75 by means of the set screws 89, and after this the back plate can no longer be vertically displaced unintentionally.

The front plate 77 is connected to a plate 98 via an intermediate plate 91 and fixed to the beam 68 . On the front side of the intermediate plate 91, the long holes 97 of the plate 93 are used for mounting.
A projection 95 is provided that projects inward. The elongated hole has the largest dimension in the horizontal direction. For attachment, the plate 93 is provided with a screw 99 that presses the T-shape 95 from the outside. By turning these screws with the screwdriver 101, the intermediate plate 91 and therefore the entire camera 78 can be moved to the left or right as shown by the arrow 108. A protrusion 95 projecting into the elongated hole 97 prevents the intermediate plate 91 from moving or rotating in a direction perpendicular to the mounting plate 98.

An adjustment ring 105 is screwed onto the threaded sleeve 79, into which an imaging thread 107 constituted by a lens system is screwed.

This imaging system 107 can be moved along the optical axis 109 as shown by an arrow 111 by turning the adjustment ring 105.

The two limbs of the U-shaped coupling member 75 have constrictions 118 located above and below the center of the transducer 65, which constrictions allow the back plate 71 to move along the vertical axis 115 passing through the two constrictions.
It can be rotated around the previous ei77. For this purpose, the back 1N71 is provided with two adjusting screws 117 that push against two side plates 119 fixed to the target plate 77. When these adjustment screws are turned in the opposite direction with screwdriver 121, back plate 71 turns in the direction of arrow 128.

A protrusion 125 is provided on the lower side of the front plate 77.

Two adjusting screws 129 are provided on the rims of the U-shaped holder 129 fixed to the intermediate plate 91, which rims extend on either side of said projection. The adjustment screws push the protrusion 125 from the left and right sides, respectively.

When the adjusting screw 127 is turned in the opposite direction by the screwdriver 181, the camera 78 is rotated in the direction of the arrow 188 with respect to the intermediate plate 91 with the axis aligned with the optical axis 109. Set screw 1
86 allows the intermediate plate 91 to be fixed to the front plate 77, and after this it can no longer be rotated in the direction of arrow 188.

From the above description, it can be seen that the adjustment means described above allows the transducer 65 to move in three orthogonal directions with respect to the imaging system 107 and to rotate around two orthogonal axes. The eight moving directions are the direction of the optical axis 109 ((mark 111), the direction of the joint surface perpendicular to this direction (arrow 81), and the horizontal direction (arrow 10).
3).

Two rotations take place around the rigidity of the optical axis (arrow 133) and around an axis 115 perpendicular to this optical axis and to the longitudinal direction of the transducer 65 (arrow 123). Since such adjustment is possible, the predetermined stripes of the document 5 to be scanned can be clearly projected onto the transducer 65. The sharpness of the image is adjusted by the movement of arrow 111 and the rotation of arrow 128, so that the distance between transducer 65 and document 5 is constant over the length of the transducer.

The positions of the imaged stripes on connection 5 are indicated by arrows 81 and 108.
is selected by movement in the direction of arrow 188 and rotation in the direction of arrow 188.

As can be seen from FIG.
1 and 48 several times.

- Figures 8 and 4 show simplified diagrams of the optical path in the plane of the drawing.

In FIG. 8, there are two linear photoelectric converters 187 and 139, each of which has an individual image thread 141 and 148 as shown in FIG. 2, for example. Therefore, in this embodiment, N is two.

Transducers 187 and 189 have 512 and 2048 photosensitive elements, respectively. These together are the thin strip part 1 of the document.
45, ie transducer 187 scans strip 147 and transducer 189 scans strip 149. Stripes 147 and 14
9 are adjacent to each other and on a line with each other. These stripes together form a long portion 145 of the document. The optical path from strip 147 to transducer 187 is diagrammatically indicated at 151, while the optical path from strip 149 to transducer 189 is schematically indicated at 158. Since it can move in the direction of arrow 81 as shown in FIG.
and 149 can be overlapped by relatively shifting them in a direction perpendicular to the paper plane of FIG. 8 so that they match exactly. arrow 188
The two stripes 147 and 149 prevent the scanning portion 145 from becoming a wide strip.
can be in the same direction, while movement in the direction of arrow 108 is such that these two strips do not overlap each other or have gaps between them. It can be used to precisely adjoin bands to giants. As can be seen from FIG. 8, the father exchangers 187 and 189 are aligned with each other after these wM alignments are performed. There is a space 1-55 between the two transducers.

The two transducers 187 and 189 have a total of 2560 photosensitive elements. Assuming that the length of the scanning portion 145 is 217 lines, the scanning resolution is approximately 11.8 lines per inch (800 lines per inch), which satisfies even the most stringent requirements currently placed on commercial digital facsimile systems. It is something. This would of course be true even if only one transducer with 2560 photosensitive elements was used. However, in this case even more stringent demands are placed on the imaging system, in that it must image significantly larger objects with high sharpness without actually increasing the size of the device. This image thread is therefore considerably more expensive than one using two image threads 141 and 148. 256
Exactly the same applies to the transducer if one uses a transducer with an image point of zero.

FIG. 4 shows yet another embodiment. In this embodiment, the image threads 1flz (, 165 and 167 (N=8) belonging to each
Eight transducers 157, 169 and 161 are used with . Transducers 157 and 161 are each zo48flN
The transducer 159 has 1024 photosensitive elements. Together they scan a narrow elongated section 169 of the document, which consists of eight narrow stripes 171, 1'? ! 1 and 175, these strips are longitudinally adjacent and each strip is scanned by one of the transducers. The eight optical paths are shown diagrammatically at 177° 179 and 181. Adjustments to the image system of these eight converters are performed in the same manner as in the embodiment of FIG. After alignment, the eight transducers are aligned with spaces 188 and 185 between adjacent transducers. The eight transducers 157, 159 and 161 have a total of 6120 photosensitive elements. If the length of the scan portion 169 is 484 lines, the resolution is still 11.8 lines per line. .

Since the size of an A2 size document is 420 x 594 mm2, the length of scan M; 169 sufficiently encompasses the width of such a document. It is acceptable even if there is a slight difference in the dimensions of the document or the placement of the document. Therefore, this embodiment is more suitable than the embodiment of FIG. 8 for scanning large sentences pJ with the same resolution.

If the table 8 (see FIG. 1) is suitably partitioned and this scanning method is carried out, the embodiment of FIG. 4 allows small documents to be scanned with the same resolution. FIG. 5 shows the section of table 8 for this purpose. The dimensions of this table are 484 x s g BJ, which is large enough to fit A2 size. Scanning portion 169 moves in the direction of arrow 188 across the length of the table as described in FIG. If an A2 size document has to be scanned, this document will occupy the entire table 8. In this case, the strip 169 is moved over the entire length of the table 8. An A8 size document has half the surface area of an A2 size document, so it has two squares, 186 and 186.
The half of the table 8 formed by 87 can be placed as desired. When the scanning part 169 is moved only over half the length of the table 8 (up to 1139), the A8 size document is scanned in its width direction.

An A4 size document corresponds to rectangle 186. This document is 51
By reading only half of the zo photosensitive elements,
Scan along its length in the direction of the hand.

I can do that. Therefore, in this case only transducer 161 and the adjacent half of transducer 159 are used. It will be appreciated that each table size is suitable for scanning smaller size transverse axes in a similar manner.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional diagram of an embodiment of the device of the present invention, Fig. 2 is an exploded perspective view of the camera system of the device of Fig. 1, and Fig. 8 is a simplified optical path of an embodiment of the device of the present invention. 4 is a simplified diagram of the optical path of another embodiment, and FIG. 5 shows an example of the division of the document table of the apparatus of the present invention. 5... Document 65... Photoelectric conversion device 1
07... Image thread 109... Optical axis 115.
...Rotation axis 187.189, 157, 159't161...Photoelectric converter 141.141, 1681165.167...
Image system 145.169...Scanning part 1551183.185-...Space.

Claims (1)

Claims: 1. at least two linear photoelectric transducers; an optical system for imaging an elongated portion of a document onto said transducers; In an optical document scanning device having a movable part that moves the part in a direction perpendicular to the longitudinal direction of the part, the imaged part of the document is
As a larger integer, the device has N linear photovoltaic transducers aligned with a space between adjacent transducers, with Nll1 longitudinally adjacent narrow stripes; Apparatus for optical scanning of documents, characterized in that the system has N imaging threads each associated with a transducer, and is provided with an adjusting device for moving each transducer relative to its associated imaging system. 2. The adjustment device can be moved in two directions: along the optical axis of the imaging system and at right angles to the σ optical axis, and at right angles to said optical axis and the longitudinal axis of the transducer. 2. Optical scanning loading of a document according to claim 1, wherein the document is rotated about an axis.